Method for producing insulated pipes

Abstract

Described herein is a process for producing insulated pipes including providing a media pipe and a film hose continuously formed from a film or a media pipe and a jacketing pipe, wherein the media pipe is arranged inside the film hose or the jacketing pipe and a slot is formed between the media pipe and the film hose or jacketing pipe, wherein an adhesion promoter is applied to the surface of the media pipe facing the film hose or the jacketing pipe, introducing a polyurethane system at least including an isocyanate component (a) including at least one isocyanate, a polyol component (b), and at least one catalyst into the slot before the adhesion promoter is fully cured, and foaming and curing the polyurethane system. Also described herein are insulated pipes obtainable or obtained by such a process.

The invention claimed is: 
     
       1. A process for producing insulated pipes, the process comprising the steps of:
 (A) providing a media pipe and a film hose continuously formed from a film or a media pipe and a shell pipe, wherein the media pipe is arranged inside the film hose or the shell pipe and a slot is formed between the media pipe and the film hose or shell pipe,
 wherein an adhesion promoter has been applied to a surface of the media pipe facing the film hose or the shell pipe; 
 
 (B) subsequently introducing a polyurethane system at least comprising an isocyanate component (a) comprising at least one isocyanate, a polyol component (b), and at least one catalyst into the slot before the adhesion promoter is fully cured; and 
 (C) foaming and curing the polyurethane system, 
 wherein the adhesion promoter is selected from the group consisting of adhesion promoters including polyurethanes, 
 wherein the adhesion promoter has a bulk density, determined without solid fillers, in the range from 400 to 1200 kg/m 3 , and 
 wherein a measure of the axial shear strength between the media pipe and the polyurethane system is in the range from 0.05 to 0.50 MPa. 
 
     
     
       2. The process according to  claim 1 , wherein the adhesion promoter is a 2-component system. 
     
     
       3. The process according to  claim 1 , wherein the adhesion promoter comprises at least one isocyanate component and one polyol component. 
     
     
       4. The process according to  claim 1 , wherein the adhesion promoter is applied by spraying or spread coating. 
     
     
       5. The process according to  claim 1 , wherein the adhesion promoter covers a proportion of the surface of the media pipe facing the film hose or shell pipe in the range from 50% to 100% of the surface. 
     
     
       6. The process according to  claim 1 , wherein the polyol component (b) comprises at least one compound selected from the group consisting of chemical blowing agents, crosslinkers, chain extenders, additives, and physical blowing agents. 
     
     
       7. The process according to  claim 1 , wherein the reaction of the isocyanate component (a) with the polyol component (b) is performed at an index in the range from 95 to 240. 
     
     
       8. The process according to  claim 1 , wherein the shell pipe or the film hose consists of a thermoplastic.